The present invention relates to quantum information processing with superconducting circuits in the microwave domain, and more specifically, to a cavity-filtered qubit or readout resonator filtered qubit.
A photon is an elementary particle, the quantum of light and all other forms of electromagnetic radiation. A photon carries energy proportional to the radiation frequency but has zero rest mass.
In circuit quantum electrodynamics, quantum computing employs nonlinear superconducting devices called qubits to manipulate and store quantum information, and resonators (e.g., as a two-dimensional (2D) planar waveguide or as a three-dimensional (3D) microwave cavity) to read out and/or facilitate interaction among qubits. As one example, each superconducting qubit may comprise one or more Josephson junctions shunted by capacitors in parallel with the junctions. The qubits are capacitively coupled to 2D or 3D microwave cavities. The electromagnetic energy associated with the qubit is stored in the Josephson junctions and in the capacitive and inductive elements forming the qubit. To date, a major focus has been on improving lifetimes of the qubits in order to allow calculations (i.e., manipulation and readout) to take place before the information is lost due to decoherence of the qubits.